It applies to the field of lithography with a tunable variable shaped electron beam, according to which an electron beam transmitted by a machine has a shape which can be tuned thanks to mobile try squares. The tunable shape is usually rectangular and the lateral dimensions of this rectangular shape are tunable thanks to the try squares.
The invention applies more particularly to a method of this type comprising the following steps:                modelling of the pattern by breaking down this pattern into a set of elementary geometric shapes intended to be printed individually by tuning the shape of the electron beam in order to reproduce said pattern, and recording of the model obtained in memory, and        for each elementary geometric shape of the model, determination, by a processor having access to the memory, of a dose of electrical charges to be applied to the electron beam during the individual printing of this elementary geometric shape, this dose being chosen from a discrete set of predetermined doses recorded in memory.        
Electron beam lithography cannot dispense with a phase of preparing the pattern to be printed because of the proximity effects caused by the diffusion of the electrons, chemical species in the resin, or other effects liable to deform the pattern to be printed, and that it is necessary to compensate. In general terms, a well known method consists of modelling the pattern by a set of simple elementary geometric shapes, for example rectangles, which can each be printed individually by exposure to the variable shaped electron beam for a certain length of time (referred to as the exposure time). The set of geometric shapes does not precisely correspond to the contours of the pattern but, by judiciously parameterising the exposure time and by allocating for each a dose, previously calculated, of electrical charges to be applied to the electron beam for printing thereof, the pattern can be printed with satisfactory precision and having compensated for the aforementioned effects.